It can be transparent to translucent; has a vitreous luster; and has perfect cleavage on { 100 }.
12.
Its color varied from dark green to puce and purple, and colorless transparent rough crystals having remarkably perfect cleavage were sometimes observed.
13.
Zorite has perfect cleavage along the planes { 010 } and { 001 }, while having poor cleavage along the plane { 110 }.
14.
Perovskite crystals have been mistaken for galena; however, galena has a better metallic luster, greater density, perfect cleavage and true cubic symmetry.
15.
As the crystals themselves possess perfect cleavage, they are typically left " in situ ", the entire aggregate often cut into slabs and polished.
16.
Kyanite has been used as a semiprecious gemstone, which may display cat's eye chatoyancy, though this use is limited by its anisotropism and perfect cleavage.
17.
It has a perfect cleavage, its colorless to pink brown with a density of 3.03 g / cm 3 and hardness of 2-2.5 gypsum.
18.
Celsian shows a c ( 001 ) perfect cleavage and a b ( 010 ) good cleavage, which marks the difference with its polymorph paracelsian which has a [ 110 ] indistinct cleavage.
19.
The structural basis of this mineral is determined to be phyllosilicate within the pyrosmalites due to the octahedral structure, with one perfect cleavage, a hardness of about 4.5, and a streak of light brown.
20.
The folia have a pronounced pearly luster, owing to the presence of a perfect cleavage parallel to their surfaces : they are flexible but not elastic, and are usually arranged radially in fan-like or spherical groups.
